NGK

NGK is the Nales Geometry Kernel: an experiment in building a geometry kernel around generalized maps, or GMaps.

The project explores how geometric modeling operations can be represented by a combinatorial topological structure first, with geometry attached as payload data. In a GMap, shapes are decomposed into small topological elements called darts. Involutions link those darts across dimensions, so vertices, edges, faces, shells, and higher-dimensional cells are described by traversal through the map rather than by ad hoc mesh records. This makes operations such as sewing, unsewing, extrusion, and cell traversal explicit in the topology, while coordinates and geometric data stay layered on top.

This repository currently contains:

• A Rust kernel under src/.
• Python bindings built with Maturin.
• WebAssembly bindings for browser experiments.
• A React Three Fiber visualization app under visualization/.

NGK is pre-alpha software. The public API, file compatibility, and modeling coverage will change as the kernel evolves.

Python package

Install the minimal native package with:

pip install ngk

The optional OCP viewer bridge is kept out of the core dependency set. Install it when you want to display shapes through ocp_vscode:

pip install "ngk[ocp]"

The Python API follows the kernel's domain structure. ngk.modeling exposes edge, profile, face, sheet, and solid construction and operations: sweep, revolve, loft, rigid motion, blending, healing, edge splitting, and face and solid Booleans. Face Booleans and edge splits return one model together with all result handles. ngk.measurement exposes length, area, volume, centroid, and inertia. STEP text exchange is available under ngk.exchange.step.

The WASM binding exposes the same modeling, measurement, rigid-motion, and STEP text capabilities. Its browser API uses camel-case exports and omits filesystem-only STEP functions.

from ngk.geometry import Frame, Point, Vector
from ngk.modeling import booleans, solids
from ngk.viz import ocp

frame = Frame.from_xy(
    Point(0, 0, 0),
    Vector(1, 0, 0),
    Vector(0, 1, 0),
)
base = solids.block(40, 30, 20, frame=frame)
tool = solids.cylinder(8, 30)
result = booleans.cut(base, tool)

ocp.show(result)

ngk.viz.debug.show can send objects to the NGK debug viewer, but the viewer is not bundled with the wheel: start it separately from an NGK checkout before using that bridge.

The bindings are experimental and the kernel is not yet a complete build123d or OCCT replacement.

Experiments

The visualization playground is published with GitHub Pages:

https://jojain.github.io/ngk/

The NGK Sandbox is published from the same Pages site:

https://jojain.github.io/ngk/sandbox/

It displays small interactive experiments for inspecting generated geometry and topology-backed modeling operations. The app is intentionally a playground: it is useful for trying ideas, checking behavior visually, and making the kernel's internal structures easier to reason about.

Local Development

From the repository root, the Rust checks are:

cargo fmt
cargo clippy --all-targets --all-features
cargo test --all-targets --all-features

To run the visualization app locally:

cd visualization
npm install
npm run dev

See visualization/README.md for details about adding new experiments.

Python releases

Prepare the next version with the repository helper:

uv tool install --editable ./release
bump

To let the tool create the commit and annotated tag from a clean master checkout, use --release directly:

bump patch --release
git push origin master --follow-tags

The --release command changes Cargo.toml and pyproject.toml, refreshes uv.lock, commits those files, and creates vX.Y.Z; it never pushes or uploads to PyPI itself.

Architecture Notes

• Architecture index: subsystems, reviews and decisions
• Vocabulary

License

NGK is licensed under the MIT License. See LICENSE.